During X-ray imaging, an object to be examined by way of X radiation generally causes scattering of an X radiation emanating from a focus in the direction of a radiation detector. The scattered radiation leads to a distortion of the attenuation values, acquired with the detector, of the X radiation and, finally, to artifacts in the X-ray images produced. In order to suppress and/or absorb the scattered radiation, use is made of scattered radiation collimators, also denoted as radiation collimators, placed directly upstream of the detector.
As a rule, the radiation collimators comprise a multiplicity of thin plane parallel collimator blades, absorption surfaces of juxtaposed collimator blades facing one another. In order to absorb the X radiation, the collimator blades are produced from a material that strongly absorbs the X radiation. Collimator blades produced from metal are also termed collimator plates.
For the purpose of acquiring the X radiation, it is known to use a detector with a multiplicity of individual detector elements that are arranged in a linear fashion, for example like a matrix. In order to avoid crosstalk between neighboring detector elements, the latter are separated from one another by septa.
In order to avoid shading of the detector elements by the collimator blades that is deleterious to the image quality, it is necessary for the collimator blades to be aligned exactly in the beam path of the X radiation and to be positioned precisely over the septa.
To this end, during production of the radiation collimator it is known firstly to position and align the collimator blades with accurate spacing by way of a holder. Subsequently, the collimator blades are interconnected and fixed. By way of example, use is made for fixing purposes of fixing elements with comblike serrations that are introduced into spaces formed between the collimator blades, and are bonded to the collimator blades by way of an adhesive.
A disadvantage here is that the thin and mechanically unstable collimator blades can easily be flexed or bent in conjunction with shrinkage of the adhesive normally occurring upon hardening of the latter. Consequently, the previously exact alignment of the collimator blades is changed. Impairment of the alignment can also be caused by the fitting of the fixing element or by other effects during production. The result of this is that the collimator blades can no longer be positioned exactly over the septa, and so shading of detector elements cannot be reliably avoided despite an exact positioning of the radiation collimator. This detracts from the sensitivity of the detector and leads unavoidably to artifacts in the X-ray images.